A micro-electromechanical system (MEMS) device may have components within the micrometer size range and sometimes within the nanometer size range. A typical MEMS device may include processing, analog, or logic circuitry as well as mechanical components for various types of sensors. These sensors may be used as part of a Radio Frequency (RF) switch, gyroscope, accelerometer, or motion sensor.
The mechanical components of MEMS devices are often provided in chambers, in which the components are allowed to move. Often there are two chambers connected through one or more vias. One way to form such chambers is to use a sacrificial material. Specifically, a cavity is formed into a particular layer. That cavity is then filled with a sacrificial material. Subsequent layers may then be deposited on top of the sacrificial material. A via is then formed through the subsequent layers to expose the sacrificial material. The sacrificial material can then be released through various chemical processes. While this is an effective way to form chambers, it is desirable to minimize the number of sacrificial layers when fabricating MEMS devices.